﻿// Copyright 2016 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using UnityEngine;

namespace GVR.Samples.SkyShip {
  /// <summary>
  ///  This component attempts to push away obstacles that travel through it.
  /// </summary>
  public class PushZone : MonoBehaviour {
    [Tooltip("Magnitude of force to push objects = pushforce * eval(forceCurve)")]
    public float PushForce;

    [Tooltip("Eval(forceCurve)'s x-value = distance from pushzone to intersecting obj")]
    public AnimationCurve ForceCurve;

    public void OnTriggerEnter(Collider col) {
      Rigidbody r = col.attachedRigidbody;
      Vector3 offset = new Vector3(col.transform.position.x - transform.position.x,
                                   col.transform.position.y - transform.position.y, 0);
      float pushforceModifier = ForceCurve.Evaluate(offset.magnitude);
      if (r != null) {
        r.AddForce(offset * PushForce * pushforceModifier, ForceMode.Acceleration);
      }
    }
  }
}
